Slideshow: Road to 400G Ethernet

“You want to reduce the number of signals to increased product density, but that will raise challenges in speed and modulation,” D’Ambrosia said noting some options in the number of fibres, lambdas and symbols the standard could specify.

Modulation schemes including NRZ and PAM and new forms of forward error correction are up for consideration, too, he said. The group also must determine how to support optical transport networks, Energy Efficient Ethernet and auto-negotation of data rates while keeping latency low.